Behavior of hadrons at finite density. Lattice study of color SU(2) QCD

Using two-color lattice QCD with Wilson fermions, we report a study of the finite baryon number density system with two-flavors. First we investigate the Polyakov line and thermodynamical quantities in the (κ,μ) plane, where κ and μ are the hopping parameter and chemical potential in the fermion action, respectively. Then we calculate propagators of meson (q-bar Γq) and baryon (qΓq) states. We find that the vector meson propagators are strongly modified in large μ regions, indicating the reduction of the mass. This anomalous behavior of the vector meson is observed for the first time in lattice QCD